Building automation systems (BAS) are used to coordinate, manage, and automate control of diverse environmental, physical, and electrical building subsystems, particularly HVAC and climate control but also including security, lighting, power, and the like. Typical existing BAS systems are hardwired or use a proprietary communication standard or protocol to link the various subsystems and provide system-wide user access and control.
Hardwiring and manual programming of BAS systems can create a robust fixed system customized for a particular installation. These systems, however, often require extensive customization for each building or site. Particular manual programming and other installation elements may not be applicable to other systems, contributing to the costliness and time-consuming installation associated with such systems.
Further, hardwired systems and those using proprietary communication standards and protocols are difficult or impossible to integrate with system components, panels, and other elements from different vendors or generations. For example, a campus of buildings in which an upgraded BAS is being installed may have existing previous generation (legacy) systems and systems from more than one vendor. Installing a BAS and making it compatible with the existing systems in such a situation is time-consuming, requiring extensive manual service and programming to integrate the existing devices and implement the custom BAS. Manual service is typically provided by systems integration personnel. While systems integrators are not favorably viewed by BAS owners and managers because of the expense and interruption, systems integrators are a key aspect of the business models of many BAS manufacturers and vendors as revenue generation and on-site contact after the sale and initial installation of BASs. BAS manufacturers and vendors have therefore been reluctant to alter their models and eliminate systems integrators.
With the introduction of BACnet™, an ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) and ANSI (American National Standards Institute) protocol standard, and LonTalk™, a protocol integration approach developed by Echelon, some uniformity of standards and communications has been achieved in the industry. BACnet™ was intended to standardize HVAC interoperability and serve as a solution to industry-wide issues. In use, however, BACnet™ exists in multiple versions and includes various non-standard feature functions available to vendors. Many vendors dictate a particular BACnet™ version that must be used in order to achieve system compliance, forcing BAS users to update. BACnet™ is therefore not completely interoperable across versions and features. Further, present BASs are typically single protocol architectures. Thus, while a given BAS is “compatible” with a protocol standard, the BAS is natively compatible with only a single protocol, such as BACnet™, another standard protocol, or a proprietary protocol.
In a simplified analogy, a BAS can be compared to a bound book. Each installation of the BAS is a different reader of the book. The book may contain multiple chapters or sections and must be custom written and professionally bound for each reader. The chapters may each be written in a different language, if the BAS is compatible with multiple protocol versions or vendors. To read the various different languages that are in the book, the reader will need to manually consult a dictionary to translate each chapter into the reader's primary or preferred language. Multiple dictionaries may be needed. The reader may not be able to completely translate each language, or may only be able to translate some chapters into non-preferred languages in which the reader is merely conversant but not fluent, and therefore the reader may only obtain a basic understanding of one or more chapters. For example, one chapter of the book might be a first language representing a particular vendor's preferred or native version of BACnet™ for the BAS, while another chapter of the book represents another vendor's version of BACnet™ in a second language. If the second language is not one understood by the reader, the reader may only be able to become minimally proficient in the second language using the dictionary to translate. Without complete fluency, the book is not useful to the reader for high-level tasks or communicate effectively. Some languages may be untranslatable, requiring the reader to consult a translator to manually translate the chapter or chapters. Manual translation in particular is time-consuming and expensive, and if whole chapters are translated, the entire book must be professionally rebound to permanently incorporate the translated material. Without professional rebinding, the reader will need to repeat the manual translation the next time the book is read.
Additionally, BAS installation and maintenance are still generally labor-intensive custom tasks that vary with each system implementation. Upgrading, expanding, and updating or removing system components and services in particular are also complex tasks, as the existing BAS may or may not support new devices and must be manually reconfigured to recognize and incorporate changes. In a common scenario, a user managing a building site with two control units operating in an existing BAS wants to add a third control unit in a newly constructed wing of the building. The user must upgrade the existing control units to the new version of the third control unit in order for the system to be compliant because the system cannot accommodate multiple versions or integrate the new control unit.
Returning to the book analogy, then, when updates to chapters in the book are necessary, or when whole new chapters are added, the entire book must be returned to the original author to be rewritten and subsequently professionally rebound. Any dictionaries must also be updated accordingly and manual translations repeated. Updates and additions are therefore labor-intensive and time-consuming to accomplish.
Existing BASs also do not offer the accessibility, customization, and management tools desired by system users. Current BASs are difficult and communicatively cumbersome to manage on a large scale, such as by a regional or nationwide retailer or other organization. Further, while Internet-based and accessible systems are presently available and in use, these systems suffer from several drawbacks. Many current Internet BASs were created as add-ons to existing BASs and thus have integrated and proprietary designs. These systems do not offer the adaptability and extensibility necessary to interface with non-native systems and sub-systems, a particular issue with respect to large-scale systems implemented in existing structures. Existing system also do not provide higher-level extensibility, configurability, and customization tools.
More recently, ASHRAE has released an XML and BACnet™ web services interface specification. According to ASHRAE, the interface is intended to be communication protocol neutral in that defined web services can be used with any underlying protocol. This approach is a least common denominator approach that can span multiple BACnet™ version specifications, wherein BAS services are supported by the intrinsic functionality of the protocol. This approach, however, still requires a gateway or translation to normalize special or proprietary functions and also requires translation or normalization between protocols rather than more smoothly running each protocol natively. Further, while the functions can be translated or normalized, data is often not given complete semantic meaning or context. In other words, while least common denominator systems can recognize data as red, blue, or green, these systems cannot recognize shades of these colors, and data loses some level of meaning when generalized to only the primary color.
For these and other reasons, a need remains for an intelligent BAS having a flexible and dynamic architecture and providing increased communication, management, and control options, particularly from a user perspective.